After graduating from the Chiavari Art Institute, Altmann arrived in Florence, where he attended the studio of Maestro Pietro Annigoni.
Inspired by classical art and fresco techniques, he chooses large surfaces for his painting and in the following years he will execute numerous large canvases, frescoes and murals also in institutional spaces and churches. To mention a few; the large mural of the Sanctuary of N. S. Della Guardia in Velva, the Via Crucis in N. S. della Speranza in Casarza Ligure and the San Sebastiano in Portofino.
His interest in classical art and technical research lead him to a stylistic expertise that allows him an expressive freedom that does not stop at classicism, but is open to all expressive aspects of the figurative arts and also to the trends of contemporary art.
In the 80s he dedicated himself to the execution of frescoes, following the rigor of the trade and driven by the desire to deepen his knowledge of the classics of the 15th, 16th and 17th centuries.

The first ten years of his activity as a painter reveal the influences that shaped him and at the same time a technical mastery that will later allow him to tackle personal research with a critical sense, never closed in a classicism but aimed at everything that is true painting.
He compares himself with the research of the 20th century: above all abstractionism, informal art, abstract expressionism, artistic movements that mark all his production.
After a short period in New York (in Greenwich Village), he returned to Italy and soon left for Zurich, where he worked on private commissions for many collectors.
It is from this period that he met an art dealer who would organize exhibitions in Germany and South Africa. Altmann is of particular interest to many collectors who love abstract expressionist art and gestural signs.

In the 90s he moved to Holland thanks to contact with the Amsterdam Siau Gallery, which promoted his works, with numerous exhibitions both in Amsterdam and in Hamburg, Lübeck and ‘s-Hertogenbosch. Returning to Italy at the end of the 1990s, he collaborates with numerous galleries in Florence, Genoa, Siena and Rome and creates numerous personal exhibitions where he expresses continuous renewal and above all expressive research on form.
The “gestural works”, built on Renaissance-inspired drawing and the abstract expressionist gestural sign, are from this period, which will make a Dutch critic, Marteen Beck’s, coin the definition of his pictorial style with the term Renaissance expressionism.

Also in the 1990s he opened two painting schools, one in Sestri Levante and one in Siena, where he taught classical techniques with a personal method of academic and contemporary teaching. Reflecting his own artistic experience, he wants to convey to young students that there is no clear boundary between styles of different eras, but that it is necessary to study the creative act in depth through gesture, sign and composition.
In recent years up to today he has dedicated himself to ever new interpretations of the figurative form
In 2010 he created an important exhibition of large canvases in Miami, at the Nina Torres Art Gallery.
From 2010 to today he has carried out numerous happenings, composing large canvases extemporaneously in front of the public, collaborating with artists in numerous theatrical plays, such as in the latest experiences of Moby Dick and The Divine Comedy, performing with live musicians and also experimenting with stage direction.